Defraggler extremely slow on large FAT32 drive

[Therix]

I have a brand new Seagate Barracude ST31500341AS 7200.11 1.5 TB drive that is formatted in FAT32 (it needs to be FAT32 for what I use it for). It's currently 50% full (4000 files, 150 folders) with mostly large (500+ Megs) files, current drive fragmentation is 6%, cluster size is 32k. I tried to run Defraggler on it and after 48 continuous hours running it was less than 10% complete, all it had done was move a few red blocks of data at the end of the drive. I'm using version 1.10.143 on a Core 2 Duo 2.6 GHz with 4 Gigs memory (3.25 recognized by the OS) running 32-bit Windows XP, System Restore is disabled.

 

Is it normal? Is there a problem with the software? I just downloaded version 1.11.148 and I'll try it again [EDIT] Processing speed seems the same with the new version.

 

My other smaller (320 Gb - NTFS) drives in the same machine defrag quickly and painlessly.